598469 A safety valve (60) for a milker unit backflush system is disclosed. The safety valve (60) comprises a housing defining a milk inlet (62), a milk outlet (64), a milk passage extending between the inlet and the outlet, a backflush fluid inlet (186) and a backflush fluid conduit extending between the backflush inlet and the milk inlet. A first seal (96) is mounted in the backflush conduit and a second seal (94) is mounted in the milk passage. A backflush piston (120) is disposed in the housing for movement between a milking position in which the backflush piston (120) engages the first seal (96) and a backflush position in which the backflush piston (120) engages the second seal (94).
